The birth of cloud computing technology and the dissemination of high-end mobile devices such as smartphones and tablets have been attracting users to enjoy online games, such as a role playing game (RPG), with their devices. The users tend to play online games wherever and whenever they want.
A massively multiplayer online role playing game (MMORPG) is a type of role playing games in which a large number of players make their own characters and for gaming purposes. In the MMORPG, many players may form a guild to play a game together in the long term or a group of players may temporarily form a party to achieve a short-term goal. Thus, it may be important for a player of the MMORPG to find other players with whom he/she can compatibly play the game.